rs779619858

Variant summary

Our verdict is Likely benign. The variant received -3 ACMG points: 0P and 3B. BP4_ModerateBP6

The NM_001267550.2(TTN):​c.89936C>T​(p.Thr29979Ile) variant causes a missense change. The variant allele was found at a frequency of 0.0000465 in 1,612,942 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.00017 ( 0 hom., cov: 33)
Exomes 𝑓: 0.000034 ( 0 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

2
5
10

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:2B:1

Conservation

PhyloP100: 6.57

Publications

1 publications found
Variant links:
Genes affected
TTN (HGNC:12403): (titin) This gene encodes a large abundant protein of striated muscle. The product of this gene is divided into two regions, a N-terminal I-band and a C-terminal A-band. The I-band, which is the elastic part of the molecule, contains two regions of tandem immunoglobulin domains on either side of a PEVK region that is rich in proline, glutamate, valine and lysine. The A-band, which is thought to act as a protein-ruler, contains a mixture of immunoglobulin and fibronectin repeats, and possesses kinase activity. An N-terminal Z-disc region and a C-terminal M-line region bind to the Z-line and M-line of the sarcomere, respectively, so that a single titin molecule spans half the length of a sarcomere. Titin also contains binding sites for muscle associated proteins so it serves as an adhesion template for the assembly of contractile machinery in muscle cells. It has also been identified as a structural protein for chromosomes. Alternative splicing of this gene results in multiple transcript variants. Considerable variability exists in the I-band, the M-line and the Z-disc regions of titin. Variability in the I-band region contributes to the differences in elasticity of different titin isoforms and, therefore, to the differences in elasticity of different muscle types. Mutations in this gene are associated with familial hypertrophic cardiomyopathy 9, and autoantibodies to titin are produced in patients with the autoimmune disease scleroderma. [provided by RefSeq, Feb 2012]
TTN-AS1 (HGNC:44124): (TTN antisense RNA 1) This gene encodes a non-coding RNA transcribed from the opposite strand to the titin gene. [provided by RefSeq, Aug 2016]

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -3 ACMG points.

BP4
Computational evidence support a benign effect (MetaRNN=0.20221347).
BP6
Variant 2-178552964-G-A is Benign according to our data. Variant chr2-178552964-G-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 405001.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
TTNNM_001267550.2 linkc.89936C>T p.Thr29979Ile missense_variant Exon 335 of 363 ENST00000589042.5 NP_001254479.2

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
TTNENST00000589042.5 linkc.89936C>T p.Thr29979Ile missense_variant Exon 335 of 363 5 NM_001267550.2 ENSP00000467141.1

Frequencies

GnomAD3 genomes
AF:
0.000171
AC:
26
AN:
152168
Hom.:
0
Cov.:
33
show subpopulations
Gnomad AFR
AF:
0.00
Gnomad AMI
AF:
0.00
Gnomad AMR
AF:
0.00151
Gnomad ASJ
AF:
0.00
Gnomad EAS
AF:
0.00
Gnomad SAS
AF:
0.00
Gnomad FIN
AF:
0.00
Gnomad MID
AF:
0.00
Gnomad NFE
AF:
0.0000147
Gnomad OTH
AF:
0.000956
GnomAD2 exomes
AF:
0.0000968
AC:
24
AN:
247934
AF XY:
0.0000595
show subpopulations
Gnomad AFR exome
AF:
0.00
Gnomad AMR exome
AF:
0.000522
Gnomad ASJ exome
AF:
0.0000996
Gnomad EAS exome
AF:
0.00
Gnomad FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.0000178
Gnomad OTH exome
AF:
0.000500
GnomAD4 exome
AF:
0.0000335
AC:
49
AN:
1460774
Hom.:
0
Cov.:
33
AF XY:
0.0000303
AC XY:
22
AN XY:
726690
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
33476
American (AMR)
AF:
0.000693
AC:
31
AN:
44714
Ashkenazi Jewish (ASJ)
AF:
0.0000383
AC:
1
AN:
26132
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39646
South Asian (SAS)
AF:
0.00
AC:
0
AN:
86252
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
52634
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5766
European-Non Finnish (NFE)
AF:
0.0000108
AC:
12
AN:
1111790
Other (OTH)
AF:
0.0000828
AC:
5
AN:
60364
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.478
Heterozygous variant carriers
0
4
8
13
17
21
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Exome Het
Variant carriers
0
2
4
6
8
10
<30
30-35
35-40
40-45
45-50
50-55
55-60
60-65
65-70
70-75
75-80
>80
Age
GnomAD4 genome
AF:
0.000171
AC:
26
AN:
152168
Hom.:
0
Cov.:
33
AF XY:
0.000229
AC XY:
17
AN XY:
74326
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
41436
American (AMR)
AF:
0.00151
AC:
23
AN:
15270
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3472
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5188
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4828
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10622
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
316
European-Non Finnish (NFE)
AF:
0.0000147
AC:
1
AN:
68032
Other (OTH)
AF:
0.000956
AC:
2
AN:
2092
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.496
Heterozygous variant carriers
0
2
3
5
6
8
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Genome Het
Variant carriers
0
2
4
6
8
10
<30
30-35
35-40
40-45
45-50
50-55
55-60
60-65
65-70
70-75
75-80
>80
Age
Alfa
AF:
0.0000868
Hom.:
0
Bravo
AF:
0.000200
ExAC
AF:
0.0000414
AC:
5

ClinVar

Significance: Conflicting classifications of pathogenicity
Submissions summary: Uncertain:2Benign:1
Revision: criteria provided, conflicting classifications
LINK: link

Submissions by phenotype

Autosomal recessive limb-girdle muscular dystrophy type 2J;C1858763:Dilated cardiomyopathy 1G Uncertain:1
Oct 01, 2016
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

not provided Uncertain:1
-
Breakthrough Genomics, Breakthrough Genomics
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:not provided

- -

not specified Benign:1
Dec 09, 2024
Women's Health and Genetics/Laboratory Corporation of America, LabCorp
Significance:Likely benign
Review Status:criteria provided, single submitter
Collection Method:clinical testing

Variant summary: TTN c.82232C>T (p.Thr27411Ile) results in a non-conservative amino acid change located in the A-band region of the encoded protein sequence. This variant is also known as c.89936C>T(p.Thr29979Ile) in NM_001267550. Three of five in-silico tools predict a benign effect of the variant on protein function. The variant allele was found at a frequency of 9.7e-05 in 247934 control chromosomes, predominantly at a frequency of 0.00052 within the Latino subpopulation in the gnomAD database. The observed variant frequency within Latino control individuals in the gnomAD database is approximately 1-fold of the estimated maximal expected allele frequency for a pathogenic variant in TTN causing Autosomal Recessive Titinopathy phenotype (0.00039). c.82232C>T has been reported in the literature in individual(s) affected with HCM, without primary information, nor strong evidence for causality (AlejandraRestrepo-Cordoba_2017). These report(s) do not provide unequivocal conclusions about association of the variant with Autosomal Recessive Titinopathy. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. ClinVar contains an entry for this variant (Variation ID: 405001). Based on the evidence outlined above, the variant was classified as likely benign. -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Benign
0.25
BayesDel_addAF
Benign
-0.30
T
BayesDel_noAF
Benign
-0.32
CADD
Benign
21
DANN
Benign
0.95
Eigen
Uncertain
0.68
Eigen_PC
Pathogenic
0.75
FATHMM_MKL
Pathogenic
0.99
D
LIST_S2
Benign
0.85
T;T;T;.;T;T;T
M_CAP
Benign
0.031
D
MetaRNN
Benign
0.20
T;T;T;T;T;T;T
MetaSVM
Benign
-0.71
T
MutationAssessor
Benign
1.0
.;.;.;L;.;.;L
PhyloP100
6.6
PrimateAI
Uncertain
0.52
T
PROVEAN
Uncertain
-3.7
D;D;.;.;D;D;.
REVEL
Uncertain
0.41
Sift
Uncertain
0.0020
D;D;.;.;D;D;.
Polyphen
0.80
.;.;.;P;.;.;P
Vest4
0.27
MutPred
0.49
.;.;.;Loss of disorder (P = 0.0514);.;.;Loss of disorder (P = 0.0514);
MVP
0.41
MPC
0.22
ClinPred
0.12
T
GERP RS
5.7
Mutation Taster
=66/34
polymorphism

Splicing

Name
Calibrated prediction
Score
Prediction
SpliceAI score (max)
0.0
Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

Other links and lift over

dbSNP: rs779619858; hg19: chr2-179417691; API